The article about pencycuron (part 2)

The commercial insecticide, diazinon, was most toxic to the preparasites, followed by phenthoate, BPMC, IBP, cartap hydrochloride and buprofezin+isoprocarb. The least toxic commercial pesticide tested was the fungicide, pencycuron. Out of 12 technical grade insecticides tested, phenthoate, monocrotophos, diazinon and carbofuran were highly toxic to the preparasites followed by buprofezin, BPMC and fenitrothion. Fenthion, etofenprox, chlorpyrifos, imidacloprid and MIPC were the technical grade insecticides least toxic to the preparasites. Most preparasites survived for up to 24 h at the low insecticide concentrations. Preparasites that were exposed to BPMC for 24 h at concentrations as high as 5.0 ppm and survived the treatments infected brown planthopper nymphs. Four selected insecticides-chlorpyrifos, BPMC, imidacloprid and carbofuran-had significant adverse effects on A unka egg hatching. Eggs that were in the insecticide solution for 168 h fared poorly with imidacloprid having the best survival. No eggs hatched source to the other insecticide treatments. Three selected insecticides, BPMC, imidacloprid and chlorpyrifos, tested against adult A unka showed that most adults survived the exposure to the insecticides between 0.31 and 2.5 ppm At 5.0 ppm of BPMC or chlorpyrifos none of the adults survived, whereas with imidacloprid 70% of the adults survived Egg deposition by the surviving adults was greatly reduced in those treated with the insecticides compared with those in the controls. Seeds of the cv Carioquinha, with 22.5% of contamination by C lindemuthianum and 29.0% by R solani were utilized in laboratory and field tests. All fungicides reduced the incidence of both pathogens. Pencycuron and pencycuron + tolyfluanid were the treatments with the least percentage of seeds contained by R solani and "damping-off" in the field. The most efficient control of C lindemuthianum in seeds was obtained with tolyfluanid and benomyl, which eradicated the fungus. All treatments significantly increased the stand, when compared to the untreated control. The efficiency of the fungicides captan cymoxanil+mancozeb, fosetyl-Al, mancozeb, metalaxyl, propamocarb and thiram was investigated in the control of P deliense P capsici, as well as benomyl, captan, iprodione, mancozeb, pencycuron, quintozene, thiabendazol and thiram in the control of R solani. The work was carried out in a growth room with controlled temperature and light regimes. R solani and P deliense were more damaging to cucumber in the present study than P capsici. Based on inhibition of mycelial growth of the pathogen by different concentrations of pencycuron, the average EC-50 of the fungicide reacted to the sensitive isolates of R solani AG-4 was at 0.02 mu-g/ml. Tenfold of 0.02 mu-g/ml was used as a discriminatory concentration to detect the sensitivity of 403 isolates of R solani AG-4 to pencycuron. There were 27.94% of isolates resistant to pencycuron. The EC-50 of pencycuron reacted to R solani AG-4 KHL 2-1, KHL 15-3, KHL 8-2, KHL 14-1, PLKT 4-1, and KHL 9-1 isolates was 0.0224, 0.0225, 0.0680, 0.0627, 0.1130, or 0.2241 mu-g/ml. In this study, both temperature and pH values were able to significantly affect the sensitivity of mycelial growth of R solani to Pencycuron at 0.2 mu-g/ml. The responses of the isolates to pencycuron could be distinguished as resistance, medium resistance and sensitivity when they were cultured on potato dextrose agar at 20-24 degree C and pH 5.4. Different components of media could also change the sensitivity of R solani AG-4 to pencycuron fungicide. When R solani AG-4 used pectin as a carbon source, the sensitivity of its hyphae to the fungicide was reduced markedly. However, the results indicated that each of eight nitrogen sources in a modified medium did not affect the sensitivity of R solani AG-4 to pencycuron.
Also, the efficacy of three experimental combinations of fungicides and two fungicide combinations sold commercially was reduced. All herbicides caused visible damage to cotton plants in Tifton loamy sand soil in Georgia but not in the silty loam soil in Egypt. The most rapid recovery source to herbicide damage and the least reduction in efficacy of fungicides were observed with herbicide norflurazon. In Georgia, the efficacy of fungicides was evaluated with no herbicides for four planting dates between 29 March and 2 May. Planting on 12 and 19 April did not affect the efficacy of the fungicides chloroneb, flutolanil, pencycuron, tolclofos-methyl, metalaxyl, or pentachloronitrobenzene, but it significantly reduced the percentage of stand with carboxin

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